Radiation therapy can include X-ray therapy, gamma ray therapy, proton therapy, and heavy-ion therapy. During radiation therapy, the radiation exposure to neighboring organs can cause various side effects, referred to as “toxicity”. As a result, treatment guidelines exist that determine an upper limit on an exposure dose to an organ at risk (OAR) or a region at risk, such as the National Comprehensive Cancer Network (NCCN) guidelines and the Radiation Therapy Oncology Group (RTOG) guidelines. An OAR is an organ or a region that might be damaged during exposure to radiation therapy, and usually refers to healthy organs located in the radiation field during radiation therapy, such as parotid glands, submandibular glands, and the spinal cord in the head and neck region. OARs can include any regions of interest and are not limited to organs. Treatment planning devices, such as the Philips Pinnacle, calculate a dose distribution by optimizing the radiation intensity, the number of fractions, and a radiation direction of the treatment equipment. Constraints on the prescription dosage to the treatment region exist, and a physician is also limited on the amount of radiation to neighbouring organs, which is generally less than the regulations in the guidelines.
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as conventional art at the time of filing, are neither expressly nor impliedly admitted as conventional art against the present disclosure.